TiN coatings with no crack and uniform compact structure were fabricated on the TC4 titanium alloy by laser micro-fusion in-situ synthesized technology. The micro-structure, chemical composition and phase of the coating were analyzed, in addition, the micro hardness of the coating, bond strength between coating and titanium alloy matrix, and the wear resistance of coating were tested. The resistance of erosion of SiO2 particles with high-speed was also tested. It was found that the bonding strength of TiN coating and TC4 titanium alloy was 240–270MPa due to good metallurgical combination between them. The micro hardness of the coatings was found to reach 1550HV0.1, around 4.5 times of the matrix which is ascribed to the formation of TiN with high hardness. Moreover, the loss weight of coating wear was 14.7% of TC4 titanium alloy and the mass loss of the substrate was twice that of the coating at an erosion angle of 60°.